1. Field of the Invention
The present invention relates to circuit board mounting devices, and more particularly to a motherboard mounting device which has a standoff and a clip between the standoff and an associated motherboard.
2. Description of Related Art
A motherboard is the foundation of electronic components used in a typical personal computer system. Firm and accurate mounting of the motherboard in the computer system is important for the computer system to operate properly and reliably. An enclosure of a computer system is typically made of metallic material. Solder portions of the motherboard cannot contact the enclosure, because this causes short circuiting of the motherboard. In general, some kind of supporting device is used to mount the motherboard to the enclosure while keeping the motherboard distanced from the enclosure.
Operating frequencies of modern electronic components on the motherboard are becoming higher and higher. A correspondingly large amount of static electricity is produced, which accumulates on the motherboard. The static electricity needs to be efficiently dissipated to ground, to avoid possible damage to sensitive electronic components on the motherboard. Accordingly, supporting devices should also function to provide electrical pathways from a grounding trace on the motherboard to a ground source such as the enclosure of the computer system.
U.S. Pat. No. 4,760,495 discloses one kind of motherboard supporting device. The supporting device is pillar-shaped. One end of the supporting device is mounted on the enclosure. An opposite end of the supporting device defines a screw hole aligned with a corresponding through hole defined in a motherboard. A screw is extended through the through hole of the motherboard to engage in the screw hole of the supporting device. Generally, a plurality of such supporting devices is required. Attaching the plurality of corresponding screws to mount the motherboard on the supporting devices is unduly inconvenient and time-consuming.
Another kind of supporting device is disclosed in China patent application no. 99216650.0. The supporting device is pillar-shaped, and is made of elastically deformable and electrically conductive material. One end of the supporting device is mounted on the enclosure. An opposite end of the supporting device has a head. A center of the head is hollow, and several through grooves are defined in the head. An upper end of the head is wider than a diameter of a corresponding hole defined in a motherboard. The head is deformably pushed through the hole of the motherboard. The motherboard is thus mounted on the enclosure by a plurality of the supporting devices. However, the motherboard is typically subjected to vibration and shock during normal use. After time, the heads of the supporting devices are liable to weaken. When this happens, the motherboard may become loosened or even disengaged from some of the supporting devices. In addition, such loosening or disengagement adversely affects any electrical connection that is provided between the heads and a grounding trace on the motherboard. Grounding pathways from the motherboard to the enclosure are diminished or lost.
Accordingly, an object of the present invention is to provide a motherboard mounting device which firmly mounts a motherboard in an enclosure.
Another object of the present invention is to provide a motherboard mounting device which provides good grounding for a motherboard.
In order to achieve the objects set out above, a motherboard mounting device of the present invention includes a standoff and a generally annular elastic clip, both of which are made of electrically conductive material. The standoff includes a head, a body, and a neck between the head and the body. The clip is undulated, and defines a central opening therein. The clip has a plurality of evenly-spaced radial upper ridges, and a plurality of evenly-spaced radial lower ridges. The clip is mounted around the neck of the standoff. A plurality of the motherboard mounting devices is used to mount a motherboard to a computer enclosure. The heads of the standoffs are extended through holes of the motherboard, and the motherboard is pushed horizontally so it is sandwiched between the heads and the bodies of the clips. The motherboard is accordingly securely mounted to the enclosure. Furthermore, the upper ridges of the clips and the heads of the standoffs maintain good electrical contact with a grounding trace formed on both upper and lower surfaces of the motherboard.
Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: